Compressors and turbines of a gas turbine engine generally have a plurality of stators and rotors in sequential disposition along a rotational axis. The rotating elements, such as compressor rotors and turbine rotors, operate at a very high rotation speed, and are mounted adjacent to and/or between non-rotating structures, such as stators, within the engine. These non-rotating structures are designed to be as close as possible to the rotating blade platforms, in order to mitigate pressurized gas ingestion inside the gas turbine engine. Typically, a rim seal arrangement is provided between the blade platforms of the rotor and the adjacent non-rotating structure in order to further limit losses from the main gas path.
Various rim seal arrangements between the rotating elements, e.g. compressor rotors and turbine rotors, and their adjacent non-rotating structures, e.g. stator assemblies, have been used in the past. However, in some cases the axial space envelope of the engine is limited. The rotors may therefore not be axially positioned closer to their adjacent stators than a minimum threshold distance, due to clearance limitations imposed by the overall tolerance stack-up.
Improved rim seal arrangements are therefore sought.